Door operating mechanism



Aug. 1, 1933- J. E. BANCROFT 1,920,835

DOOR OPERATING MECHANISM Filed. Nov. 23, 1929 3 Sheets-Sheet 3 INVENTOR ([AMES E BAA/CR OF? ATTORNEY s, f "W 5 ,W. Q

Fatented Aug. 1, 193.3

DOOR OPERATING MECHANISM James E. Bancroft, Detroit, Mich, assignor, by niesne assignments, te The Peelle Company, NCW'Yi'il'k, N. 13., a Corporation of New York Application November 23, 1929 Serial No. 409,284 i 14 Claims. '(Cl. l8752) uu rreo STATES PATENT orr 1o this floor.

' This invention relates to operating mechanism for the doors of elevator hatchways, and more particularly to a power driven apparatus which will serve for all the doors of a hatchway and which will open and close the doors at any floor where the elevator car is stopped.

In'the operation of elevators, it is necessary because of safety regulations to fully close the doors at a given floor before the car can leave It follows that under ordinary circumstances the car is held stationary for a considerable amount of timewhile the doors are opening and closing, and any device which will operate the doors more rapidly is of great value 13 in permitting the car to handle more passengers or more freight in the course of a day.

This has been recognized, and it has heretofore been proposed to utilize a single power driven device for each-hatchway and to provide means iorconnecting this device to the door or doors filed March 14, 1928, I have disclosed a door operating mechanism which serves to transmit a substantially simple harmonic motion to the doors asthey open 01' close, and thereby overcomes many of the defects. in the earlier (3011-,- structions. This mechanism is, however, of the so-called individual type, in which a driving motor and connecting parts are provided for each set of doors, and the cost of such an in- 40 stallation in connection with a hatchway having a large numberoi doors is excessive. Moreover, where a complete dooroperating mechanism is used at each floor in a tall building, there is a great deal of machinery to look after and keep in repair. Because of these considerations the use of individual type operators has been largely confined to buildings having a small number of floors. 7

It is accordingly one subject of my invention r to provide a single power driven mechanism for installation in connection with an elevator hatchway having a plurality of doors which will serve to transmit a substantially simple har-, monic motion to any selected door or set of doors. i

A further object of. my inventionis to provide a door operating mechanism which will be simple and compact, and which can be easily installed in existing elevator installations having a large number of doors without requiring any important alterations inathe existing structures.

A further object is to provide a door operating mechanism which cannotbe damaged by the presence of an obstruction in the path or a door, and whichwill be'self correcting when the obstruction is removed.

A further object is to provide a mechanism for operating elevator hatchway ,d oors by power whichwill comply'with all. safety requirements; and which is so arranged that the car cannot leave a floor until the doors atthat floor are not only closed but also looked against opening from the outside, the doors cannotflb'e opened exceptwhen the car is at the corresponding floor and they can .be quickly stopped by the operator at any point in their opening or clos ing movement, and the locksmay be easilyreleased from inside the hatch and the doors opened by hand in the event of failure of the power supply.

.With these and other objects in view, as will be apparent'to those skilled in the art, my in vention resides in the combination of parts 'set forth in the specification and covered by the claims appended hereto.

. Referring to the drawings illustrating one embodiment of' my invention, and in which like reference numerals indicate like parts;

Fig. 1 is an elevation taken from inside the hatchway showing my invention applied to two sets of doors of the well known counter-balanced Fig.2 is aside elevation of the construction shown in Fig. 1; V

Fig. 3 is a top plan view of the mechanism shown in Fig. l as mounted in the penthouse;

Fig. 4: is a detail view in section showing the construction of the compressible connecting rods for theretiring cams;

Fig. 5 is a detail view showingthe construction of two of the electric switches used with my invention; U

Fig. 6 is a detail View showing the construction of the interlocking device used in connec tion with the switches shown in Fig. 5;

Fig. '7 is a perspective view showing the construction of the limit switches; y

Fig; 8 is adetail view showing the construction of the action switch operated by the retiring cam crankshaft; I a

Fig. 9 is a detail view of the zone switch mounted on the elevator oar together with oneof the cams which serve to actuate it;

Fig. 10 is a wiring diagram of the various control circuits;

Fig. 11 is a wiring diagram of the main motor circuits;

Fig. 12 is a detail elevationshowing the-external construction of the master interlock switch;

Fig. 13 is a sectional View showing the internal construction of the master interlock switch;

Fig. 14 is a side elevation showing the construction of the friction grip mechanism for one 7 of the lower doors, the friction being disengaged;

Fig. 15 is a view similar to Fig. 14 showing the relationship of the various parts when the 'fric-.. tion is engaged;

Fig. 16 is a sectional view showing the internal construction of the friction grip mechanism, the friction being shown disengaged;

Fig. 17 is a view similar to Fig. 16 but with the friction shown engaged, the section being taken on the line171'7 of Fig. 18

Fig. 18 is a section onthe line 18-18 of Fig.

Fig. 19 is a side elevation showing the friction grip mechanism for one of the upper doorswith its corresponding latch, the friction being'shown disengaged. r y

For'simplicity of illustration the invention has been shown in. connection with an elevator hatchway having but'twosets of doors. However, it will be clear from the following description that the invention is useful in connection with installations having a large number of sets of doors andthat it is particularly adapted for such purposes. i a

At each floor a-doorway 26 is provided in v the vertical wall 27 of the elevator hatchway.

In the form illustrated, the. openings 26 are arranged to beclosed by doors of the well known count-cr balanced type on the hatchwayside of the wall. 'Each set of doors comprises an upper door 29" and a 'lower door 30 of substantially equal weight which are connectedateach end by fiexible cables passing over sheaves 32 mountedalong the upper. edge of the lower door 30. The doors 29 and 30 are mounted to slide freely vertically in guides (notshown) and the parts are so arranged that any vertical move ment imparted to one of the doors will result in a similar movement of the other door but in the opposite direction. Doors of the type described are well known-in this art and are frequently operated by handalthough this method of operation is slow, inemcient and laborious.

In order to operate the doors by power I provide a single power actuated mechanism which which as is wellknown is the motion of the projection on 'a straight line of a point moving at a uniform velocity in a circular path. One suitable means for carrying-out these purposes is illustrated in the accompanying drawings and comprises a pair of vertical cylindrical rods 36 and 37 which are arranged one at each side of the doors and'which are connected at their upable guides 51.

.mounted on the wall 27. Those portions of the chains which do not pass over the sprockets during the operation of the mechanism may be replaced by rigid rods as illustrated and a turnbuckle .43 is preferably provided in the lower chain 41 in order to take up any slaokwhich mayoccur. The rods and chains thus form a continuous power transmitting circuit. The sprockets are connected by means of shafts 45 (Fig. 3) to a second pair of sprockets 46 around which passes a chain 47. A part of the upper'portion of the chain 4'7 is replaced by a rigid bar 50 slidable lengthwise of itself in suit- This bar 56 is joined by means of aconneoting rod 52 to a crank arm 53. The crank arm 53 is driven by means of an electric motor 55 through a worm and worm gear reduction 56. The revolution of th crank arm is what produces the simple harmonic motion imparted to the doors.

In order to stop the motor 55 immediately whenever the electric current supply thereto is interrupted, I-preferably provide on the shaft between the motor and the worm gear reducton 56 a solenoid released brake 5'7 (Fig. 3) having a coil 58 (Fig. 11) Brakes of this general type are well known to the artv and one suitable construction is disclosed in the patent to Peelle No.

It will be noted that in Fig. 1 the crank arm 53 is shown in one dead center position. As this crank arm is revolved by the motor in the direction'of the arrow this will cause the bar 50 to slide to the right, and the sprockets 46 and 40 willrotate in a clockwise direction thus moving the rod 36 downwardly and the rod 37 upwardly. When the motor is reversed the crank arm will move in the opposite direction and the rod 36 will be raised and the rod 37 lowered to its original position. The length of the crank arm and the ratio of the sprockets is such that as the crank arm moves from one dead center position to the other the rods 36 and 3'] will travel vertically a distance equal to the desired movement of the doors, and the rods will be started and stopped gradually in accordance with the simple harmonic motion imparter thereto.

. In order to transmit the vertical movement of the rods 36 and 3'? to the doors, I provide a suitable mechanism i'or connecting any selected set of doors to the rods. This mechanism is preferably so arranged that it will only connect a set of doorswhen the elevator car is stopped adjacent to the corresponding floor. For this purpose I provide a friction grip device or clutch 59 which is mounted upon the right hand end of the trucking bar 33 of each lower door (Fig. 1) and which is arranged to frictionally engage the rod 36 whenever it is actuated by means of a cam fiomounted upon the elevator car 61. Each friction grip device 59 comprises a casing 63 mounted on the trucking bar 33 and provided with a semi-circular groove'lined with suitable friction material 64, such asleather or rubber, (Fig. 16) which is shaped to fit against the rod 36. This r'0d'36 is arranged to be clamped be tween the casing 63 and an adjustable shoe 65 having a similar semi-circular groove therein which is lined with friction material 66.

The shoe is preferably thrown ,into engagement with the'rod bymeans of a self-lockpreferably surround pins 77 fixed in the shoe 65 and extending through openings in the plate 73. Cotters 78 through the ends of the pins 77 hold these parts in assembled relation and serve to receive the pressure of the springs 76' when the friction grip is released.

It will now be seen that when the roller is moved by the cam 60 from the position shown in Fig. 14.- to that shown in Fig. 15, the shaft 68 is rotated in a counter-clockwise direction.-

The arm 72 and the link 74 form a toggle con nection and serve to firstmove the plate 73 and shoe 65 to the right and against the rod 36 and then to compress the springs 76- and apply a substantial pressure against the rod 36, gripping the rods between the shoe 65 and the casing 63. It will alsobe seen from an inspection of Fig. 17 that when the toggle mechanism applies the gripping pressure it passes slightly beyond its center position and is, therefore, made selflocking by the pressure of the springs 76. Counter-clockwise rotation of the shaft 68 is limited by a stop 80 integralwith the/arm 69 and'arranged, to engage against the trucking bar 33 shown in Fig. 15 when. the friction grip is applied.

It'iis desirable from a safety point of view to lock the doors together in their closedpositi'on and thereby prevent anyone from opening the doors manually from a point outside the hatch.- way. For this purpose I mount on the right hand side of each upper door 29' (Fig. 1) a bar 81 which extends beyond the edge of the door and carries on its outer end a bracket 82 (Figs. 14 and 15), on which is pivotally mounted a latch or hook-shaped member v83. The latch member 83 is pivoted tothe bracket 82 at 85 and is arranged to hook beneath the trucking; bar 33 on the lower door when the doors are closed, as'clearly shown" in Fig. 14. The latch 83 is urged toward latching position by means of a powerful compression spring 86. The spring 86 bears against alug 87 on the bracket '82 and this lug also serves as a stop to prevent the latch 83 from swinging beyond the position shown in Fig. 14" after the doors have been opened. In order to release the latch when the friction grip is applied as a preliminary step in a the opening of the doors, I provide a projecting portion 89 on the arm 69 which is arranged to force the member 83 into the position shown in Fig. 15-when the friction grip is applied. When the doors start to'open under the influence of the friction grip, the latch member 83' will travel upwardly with the door 29 and slide over the surface of the trucking bar 33 which ismoving downwardly with the lower door. doors are again closed the member 83 will travel downwardly withthe upper door and because of the cam shaped curved surface 90 at its lower end it will simply ride up over the trucking bar and snap into place as shown in Fig. 14.

i The spring 86.is made sufiiciently powerful so When the that when the cam 60 is outof'the way it will force the latch 83 .into latching position .and push back-on the projecting portion 89 of the arm 69,, thereby releasing the self-locking toggleof the friction grip mechanism. In order-to insure:that thefriction surfaces will not drag against the rod 36 after it is released, I provide a weighted portion 91 on the arm 69 which after the release of the toggle will serve to rotate the shaft 68 in a clockwise direction into the position shown in Fig. 14 and bring the arm 72 againsta stop 92 (Fig. 16) on the casing 63.

- It is desirableto connect the other end of each upper door to the power actuatingmechanism in the penthouse, and for this purpose I mount oneach upper door 29 and adjacent the lower left hand corner thereof a bar 94 which is similar to the bar 81 on the right hand side thereof.

.Each bar 94carries on its outer end a friction grip device 95 v(Fig. '19) which is exactly similar to the device 59 mounted on the bar 81 except that the device 95 is arranged the other side up. Because of this reversal in position the arm 96 thereon does not require a weighted portion equivalent to the part 91 on the arm, 69,

.since the-weight of the roller 98serves to normally hold the friction released. Eacharm 96 is provided with a stop 99 and a projection 100 which are similarv to the parts 80 and 89 respectively on the arm 69.

I prefer to provide means for locking the doors to some stationary part of the structure when in a closed position as well as latching them together in the manner shown in Fig. 14. For this purpose I provide a supporting bracket 102 (Fig. 19) which is mounted upon any suitable part of thestationary structure such as the door guide rail 103"lo'cated adjacent to the vertical edge of the door. A latch member 104 is pivoted to the-bracket 102 by means of the pin 105 and is urgedtoward latching position by means of a compression spring 107. A stop 108 on the upper portion of the member 104 limits the movement imparted to it by the spring 107; This latch member 104 overlies thebar 94 on the upper door when the doors are in closed position and thus normally prevents opening thereof. When the friction grip device 95 is-engaged by means of a cam 109 (similar to cam 60) onthe elevator car 61, the projection 100 contacts with the member 104. and releases the latch thus permit ting the part 94 to move upwardly and the doors to be opened. Whenthedoors are again moved toward closed position, the bar 9% strikes against a sloping cam surface .110 on the latch member 104 and thus compresses the spring 107 until the doors have reached their fully closed position, when thelatch will snap back into the position shown in Fig. 19. The spring 107 is sufficiently powerful to release the self-locking toggle of the friction gripmechanism unless the cam 109 prevents it.

The car-115 60 and 109 may be fixed in a definite position on the elevator car, but I prefer to so arrange these parts'that the cams will retire out of their'operative position except when it is desired to' open the doors, so that they will not affect the friction grip devices. at a floor which the car passes without stopping. For this purpose I mount each cam 60 and 109 on the elevator car by means of pivoted links .112 (Fig. 2) so that as each cam is moved'upwardly it will also move outwardly away from the elevator car Whilethese cams may be actuated manuallyyl prefer to. actuate them by power, and for this a purpose I utilizean electric motor of the so called ftorque type which is arranged to be stalled .on the line. This torque motor 113 is mounted on the underside of the elevator car 61 and drives a rotatablesha'ft, 114 through a chain and sprocket connection llfin This shaft l14 is mounted in suitable bearings 117 on the at the same time serves to close: this switch,

which is normally held open by a spring 123. The closing of the switch 122 .serves to start the motor 55 in the penthouse to open thedoors in a manner to be hereinafter described.

It is necessary that the shaft 114 should reach the limit of its movement so as to close the switch 122, and in order that this may occur despite irregularities in alignment of the various friction grip devices I preferably make eaoliconvnecting rod 120 slightlycompressible. One suitable :way of accomplishing this purpose is disclosed inFig. 4. As there illustrated the upper portion 125 of each connecting rod 120 is slidable relativejto the remainder of the rod and is normally held in an extended position by a compres sion spring 126. This spring 126 is made sufficiently' strong so that the friction igrip device I will be forced into a full engage'mentand if after this has happened the switch 122 has not. been closed the spring 126 will compress slightly so as" n to permit the shaft 114 to rotate the additional amount required to close the switch.

It will be seen from Fig.2 that each crank arm .118 approaches one dead center position as the cams 60 and109 reach their fully extended positions. This gives a toggle effect to the mechanism and amplifies the force. which is transmitted to engage the friction grip devices.

The arm 121,.however, prevents the crank arms 118 from quite reaching their dead center position, and as'a result when the torque motor 113 is deenergized the cams BO-and 109 will descend upon the action of gravity into an inoperative position, the torque motor being rotated .in a counter-clockwise direction :by the weight of the cams.

' In order to'prevent any possibility of power actuation of the doors except when the elevator car is. stopped at ,a landing, I provide a zone switch-128 (Figs. 9 and 10) which is mounted upon the side of the car 61. andJis included in the door control circuit; This switch 128 is arranged-to be closed by an arm 129 pivoted at its lowerend to the car and provided at its upper end. witha roller 130. A cam .132 is mounted on the hatchway wall at each floor and arranged to contact with the roller 130 when the car is at that'fioor and thereby close the switch 128. When the car is not at a floor the switch is held open by theweight of the roller 130 andarm 129. 7

In order to stop the door actuating motor whenever the doors reach either their fully open or fully closedpositionfl provide the limit Switches 133 and 134, illustrated in detailin be opened; as shown in Fig. 7.

Various types of .motors may be used in connection with myinvcntion but in the wiring diagram (Fig. 11) I have shown the motors '55 and '113 as of the compoundwound type intended for use with. a direct current supply. The main switches which control the current flow to the motors are preferably of the well known solenoid actuated. type which normally remain open under the influence of gravity and are closed by the action of an energized solenoid. I utilize two three=pole switches 142 and 143 to control the current to the door actuating motor 55. The first of these may be closed by a solenoid 144 to operate the motor in a direction to open the doors, and the latter may be. closed by a solenoid 145- and serves topperate the motor 55 in a. direction to close the doors. Since. the torque motor 113 is not reversible a single two-pole switch 1 1-7 arranged to be closed by a solenoid 148 serves to"control.the current supply to' this motor. I

As illustrated in Fig. 5 the. switches 143 and 147 may comprise switch arms 150 and 151 respectively which. are pivotally mounted on opposite. sides .of a supporting and insulating panel 152;;The switcharms 150 and 151.,carry contact members 154 and 155 respectively which,

when these on is'closed, "engage with other contact meinLe-s 156 and 157' mounted on the panel In Fig. 5' switch 143 is shown open and switch 147' closed. It vis thought unnecessary to. iilustrateswitch 142 as it is constructed ina similar manner. to switch 143, except that it does not have the. interlocking construction to be hereinafter described.

In connection with the switches 143 and 147, I preferably utilize the construction shown and describe'cl'in my prior application Serial No. 312,- (95 filed October 12,1928. This construction mechanically interlocks the switches so'as to prevent 'their'siinultaneous closure and also ,pro-. vides furtheradvantages which will be hereinafter apparent. aninterlocking bar'159fhaving bluntly pointed ends which is pivotally mounted centrally at 1 in the panel 152. This bar 159 is normally but yieldingly held in a horizontal positionby means of a coiled spring 161. The switch arms 150' and 151 carry interlock fingers 163 and 164 respectively. These fingers carry near their upper ends small insulated blocks 165 and 166, having notches in their faces. I v I These parts are so shaped and arranged. that when-for instance the switch 147 is closed, the

- its new position prevents closure of the switch 143, and if th solenoid 145 should be energized in an attempt to close the switch 143, the insu- Asshown in Fig. 6, I provide lated block 165 would strike againstthe bar 159 and result in tipping it still farther, thus breaking its contact with the finger 164, and deen'ere.

gizing the solenoid 148, whereupon switch 147 will open. A similar result 'Will'be reached it anattempt is made to close switch 147 while .One push button 166 and one push button 167 are mounted in the elevatorcar and the others are preferably located ata point outside the hatchway at the ground floor of the building. It will be apparent that additional push buttons may be connected in parallel with those shown and located at other convenient places as desired. v 7

The operation of the various parts as so far described will now be explained with particular reference to the wiring diagrams shown in Figs.

l and 11., First assume the elevator car is brought to a stop adjacent one of the landing floors 25. As soon as the car reaches the landing the cam-132 (Fig. 9) adjacentthis landing contactswith the roller 130 on the car and closes the zone switch 128. ,The' doors, of course, have been previously closedand latchedby the mechanism shown in Figs. 14 and 19; The opfrom the power source .171 through the left pole except when the doors are fully open through solenoid 148 and then back through push button 167 to'the otherside 169' of the power supply. The instant that solenoid 148 is energized,

switch 1'47"is pulled'by the solenoid into the closed position, and at the same time interlock finger 164 contacts with interlock bar159 thus closing a circuit back to power'source 169\independent of the circuit through push button 167 and permitting the release of this-push button without resulting in a'deenergization of solenoid 148. The closure of switch 147 connects torque motor 113 directlya'cross power .su'pply"l7 l,' 172 (Fig, 11): This power supply may be the same as 168, 169 or independent thereof. Switch 147 having been closed the torque motor 113" rotates shaft 114 in aclockwise direction (Fig. 2) and moves the retiring cams 60 and 109 into operative position. These cams contact with roll ers 70 and 98 and cause the'friction grip debe released without deenergization or solenoid 145. Closure of switch 143 completes a circuit from-power'supply 171 through the left pole or vices 59 and 95 to engagethe vertical rods 36 and 37. At the-same time the arm-121' swings} with the shaft 114 and strikes the action switch 122 closing this switch and stall-ingth'etorque motor, though the current supply to the motor is. not interrupted. Closure of the switch 122 connects the solenoid l44 in parallel with 'theenergized solenoid 148, as shown in Fig. 10, thereinto closed position.- This completes a circuit of switch 142,through'the armature of the penthouse motor '55pthrough the center pole 'of to, the other side 172 of the line. time a circuit is completed from power source *171 through theshunt, field of the motorfield 55, through the right poleof switch .142 and back to theother side 172 of the line. time as theshunt field is energized the brake At the same coil 58 connected in parallel therewith is likewise energized and the brake on the motor'i.

shaft is released.

The motor as will immediately sari rotating the crank arm 53 in the direction shown by the arrow in Fig. 1, thereby causing rod 36 to move downwardly and rod: 37 to move upwardly.

Since these rods have been connected to the doors by the friction grip devices, the lower door will be pulled downwardly and the upper door 29 will be pulledupwardly. Because of the use of the crank arm 53 and connecting rod 52 startin"; and stepping on the dead center positions a substantially simple harmonic, motion will be imparted to the doors. The doors will start slowly giving the motorample opportunity to pick up'speed without overloading and the doors will accelerate to high speed and then gradually slow down to a gradual stop without slamming.

Because ofthe slow starting features there is no;

yanking on the rods 36 and 37 andvery little tendency for the rods to slip through the fric As soonas thecrankarm 53reaches its to open. The opening of these switches breaks the power supply to both the motors. Motor 55 will be brought to animniediate stop by the actionjof the brake 57,.and torque motor113 will I be reversed'by'the weight of the retiring cams and 109. It will be seen'that as thedoors move'tow'ardopen position the rollers and 98' will soon run off. from the retiring cams. This,'ho'wever,' does not permitthe release of the friction grip devices, since a self-locking toggle mechanism is incorporated in them as here tofore explained. v 1

.Assume now that the elevator operator wishes to close the doors and leave the floor. He presses push button, 166 on the car thereby completingja circuit from power supply '168}through zone switch l28,through limit switch 133, which was closed by spring immediately after the doors started to open, through solenoid- 145, through push button 166 andthus back to the other side 169 of the line. Energization of the solenoid 145'pulls switch 143 into theclosed position at'the same time bringing interlock finger independent of push button 166 which may now switch 143, through the armature of motor 55,

through the center pole of switch 143, through right pole'of switch 143 back to the other side 1722' of the. line. At the same time the shunt fieldof motor 55 and thefbrake solenoid 58"are connected directly across theline through the right pole of, switch 143. It will be seen that under these conditions the direction of current flow-through the motor armature is in a direction contrary to that occurring when switch 142 is closed, while the flow throughthejfield wind ings is the same. The motor 55 willxthe'refore start in the opposite direction. The crank arm 53 will be revolved in a direction opposite to the the series fiel'ol of motor 55, and throughthe arrow in 1, and the doors will-be'moved with a simple harmonic motion to the closed position. a As the crank shaft 53 reaches its dead center position and the doors are fully closed,

"armalzil will open-liniit switchv-l33 thus deenergising solenoid145 and opening switch 143, and

the-motor55 will be immediately stopped by the I TO action ofbrake 57. p 7 i i--If=th6 doors are movingtoward closed position and it is desired for any reason to stop their movement it is merely necessary to press push button 167 (which isthe one used for opening the; doors) thus-energizing solenoid 148. Be-

cause of the interlock b23159, the corresponding and the motor: tostoph In a similar manner the doors may be stopped during their opening movement merely by pressing the, other push button 166. Once the movement of the doors has been stopped they can be started again in either direction desired merely by pressing the proper pushbutton. .Q fyj .Because; of the simpler harmonic motion with its, gradual-. start and stopfeatures. the friction rip devicesmay be so designed that theyfwill' slipinthe eventpne of the doorsmeets anobstruction during its movement and thereby pre yentdamageto thedriving mechanism. If the doors were given a sudden start; as has been the custom-in prior constructions, the friction grip-s would have to engage the'prodsvery firmly indeed-toprevent slipping because of the inertia of the doors. ent invention, if the frictionsshould slip due'to an'obstruction they would "slip againwhen the full distan ce and the link 1990f course willleave doors came up against their stops at the end of the. door travel; the mechanism is therefore self.- correcting; and the doors will operate: in the roper manner attheir next-opening or closing.

movement. The entire mechanism is balanced and the only iorces to be overcome are those of frictionand inertia. The weight of. the rod 36 isexaetly balancedby the weight of the rod 37 I nomatterhow many 'fioors there are inv the then ope'hedby hand;

building, and theweight 'of eachlower doori3Q is exactly'halanced by. the weight of the'correspending upper door 29. In the event of failure,

of-the power supply, the latches can, be easily released -froininside the hatchway andth'e doors A- further featurepf my invention involves the use .of a 'rnaster interlock switch which is so constructed and arranged thatthefidoors must not only beclosed but also looked from inside of theQhatchWay joefore the elevator carcan leave a landing In the embodimentillustrated this master interlock is actuated by the latch members 83 shown in detailf in Figs". 14'and'15J As-the're illustrated, an interlock arm 1'75 is.

pivotally mounted at 176 on each bracket 82. Each arm 175 has integral therewith a pair of lugsl'l'l whichstraddle an upstanding lug 179 formed on; the-latch-member 83. These parts.

are soarranged that whenever the 1atch83 is released .to permitopening'the doors thearm 1'15 will swing about its pivot in a clockwise .di-

rectioninto the position shown in Fig. 15.- A

i vertical member such as a. wire 180, extendsthe With the construction of, the mesa length oi the hatchway through the ends of the arms 175 .and this wire carries a stop 181 adjaaction of a weight 133 mountedon the lower part of the wire (Fig. l). I utilize this upward movement of the wire 180 to open an electric circuit and prevent movement of the elevator car. i For this purpose I provide the interlock switch illustrated inFigs. 12 and 13. As shown in Figs. 12' and 13, this switch comprises a pair of spring contacts 184 and a movable contact member 185 which is carried by an arm 187 mounted on a shaft 188. This shaft 188 is rotatably sup-- ported in suitable hearings, in a case 189 and carries on its outer end a cam member 191. A sprocket 192 is rotatably supported on the cas- .ing 189 and a chain 193 extends from the upper end of wire 180 and around the sprocket 192 as shown in Fig.1. The right hand end of chain 193 is connected by a wire 1'95 (Fig.1) to a secend-chain 196 which passes around a sprocket 197 at the lower end of the hatchway and connects to the lowerend of wire 180. The chain lashes a special projecting link 199 (Fig. 12) whichnormally extends into a notch 200 in the cam member 191. The operation of this master interlock switch willnow be apparent; The contact members 18 1 are connected into the control circuit for the elevator car in a manner well known to those skilled the art. Whenever the interlock Wire 180 is, raised by the releasing of any one of'the latch-members 83 the projecting linkwl99 will act onthe cam 191androtate the shaft 188 in a counter-clockwise direction. This will breakthe contact betweenthe'member 185 and the left contact member 184, thus preventing operation of the elevator. Whenthe doorsare opened the wire 180 will travel'upwardly' with them for the claim as new and desire to secure byLetters Pit-t1.

ent is: I r V .1.' An operating mechanism for the slidable doors of an-elevator hatchway having an elevator car therein comprising a powcrtransmitting means: extending vertically of the hatchway, a

poweractuated'crank, means including a connectingrod pivotedto the crank and arranged to inc move the .powertransmitting means vertically,

meanspaffected by the position. of the elevator car and arranged to connectthe IJOFJGF'tYL-ZK'ET: initting means to any oneof said doors it. 7.

the elevator car is stopped adjacent thereto, and means to stop the movement of said crank reaches, either of its-dead center positions.

2. An operating mechanism for the doors of an elevator hatchway having an elevaslidable J. 5

tor 'car therein comprising. an electric motor, a

crank actuated thereby, a connecting rod to the crank; and means to transmit power from theconnecting rod toany one of said-doors when the elevator car is stopped adjacent therer to, said means including'a yieldable connection crate the motor and E. rotate the crank arm through substantially a single h" dead center .positionto the other, said connect-- tlfturn from one ing rod being so conncctedito said member that the; crank arm ison dead;v center when the doors are both fully opened and closed.

Jl. An operating mechanism for the vertically slidable counterbalanced doors of an elevator T hatchway having an elevator car therein comprising two vertically-movable power transmitting members mounted in the hatchway, one at eachside of the doors, flexible means directly connecting the upper of the members, additional flexible means directly connecting the lower ends of the members to provide a. continuous power transmitting circuit, guides for said flexible means, means effective when the elevator car is stopped adjacent to set of doors to connect the upper door of the set toone of said members and the lower door to the other of said members, a motor driven crank, and

means including a connecting rod pivoted to the. crank which transmits power to said circuit and causes the members to move with a substantially simple harmonic motion as the crank moves from one deadv center position to the other. I

5. A door operating mechanism for the doors of an elevator .hatchway comprising two rods mounted for vertical movement in the hatchway and frictional engagement with door opening devices, a flexible connecting member between the upper ends of the rods, guides therefor, a crank arm and connecting rod, a power driven mechanism, acontrol device to operate the mechanism through a definite cycle and move the crank arm from one deadcenter position to the other,

' of an elevator hatchway com -mounted for vertical movement in the hatchway and, frictional engagement and connections betweenthe crank driven connecting rod and-the flexible connecting memher, said parts being so arranged that thedoors are fully opened and closed when the arm is substantially on its dead center positions.

6. A door operating mechanism for the doors of an elevator hatohway comprising two rods mounted for vertical movement in the hatchway and frictional engagcmcntwith' door opening devices, a flexible connecting chain between'the adjacent ends of the rods, sprockets supporting the chain, one of which serves as a driver to move the rods, a power driving mechanism, and connections between. the mechanisim. and the driving sprocket to move the rods;

7. A door operating mechanis for the doors sing two rods wi 1 door opening devices, a flexible connecting chain between the adjacent ends of the rods, sprockets supporting v the chain one of which servesas a'driver to movethe rods, a 'power" driven mechanism; a

crank arm and connecting rod driven'thereby,

a control device to. rotate the crank from sub stantially one dead center position to the other, and means whereby the connecting rod isconnected to rotate said driving sprocket, said parts beingso arranged that the crank arm is substantially on its dead centers when the doors are fully open and closed.

3. A door operating mechanism having a vertically slidable rod and a friction grip device engageable therewith comprising a gripping member having a friction surface adjacent to one/side of the rod, a friction shoemovably mounted on the other side ofthe rod, andmeans including a toggle linkage arranged to move the shoe and thereby grip the rod between the shoe and said friction surface.

.9. A door operating mechanism havinga vertically slidable rod anda friction grip device engageable therewith: comprising a. gripping member having a friction surface adjacent to one side of the rod, a friction shoe movably' mounted on the other sideof the rod, a toggle linkage, and a spring connecting the linkage with the shoe, the linkage being arranged to move the shoe into contact with the rod and grip the rod between the shoe and said friction surface, and the spring serving to lock thetoggle in the over-center position whenthe shoe is in gripping position.

'10. In combination with a series of doors vmounted adjacent to openings in the walloi': 'anelevator hatchway in which an elevator car is movable, a latch adjacent to each door arranged to lock the door in its closed position, a master interlock switch, and connecting means between each latch and the switch which is so arranged that release of any one of the latches will open the switch and prevent operation of the elevator car.

11. In combination with a series of doors mounted adjacent to openings in the wall of an elevator hatchway in whichv an elevator car is movable, a latch adjacent to each door arranged to lock the door in its closed position, an interlockarm connected to each latch and arranged.

to be moved thereby, a member extending vertically of the hatchway and having a stop adja-' cent each interlock arm, and a master interlock switch connected for actuation by said member,

said'parts being .so constructed and arranged that release of any one of the latches will openthe switch and prevent operation of the elevator. 12. An operating mechanism for the doors of an elevator hatchway having an elevator car therein comprising a power transmitting rod extending vertically of the hatchway, an electric motor, a rotatable member drivenby the motor,

connecting means between the member and the' rod, said connecting means and the rotatable member havingtwo dead center positions, connecting mechanism adjacent to each door arranged to connect the door with the rod, means affected by the position of the elevator -car and arranged to render each connecting mechanism effective only' when the car is stopped adjacent thereto, an electric switch to start the motor, anda limit switch to stop the motor as the rotatable member reaches either dead center position, whereby the doors are moved through a predetermined distance with a linear-velocity which smoothly and gradually approaches zero at each limit of travel.

13. An operating mechanism for the vertically slidable counter-balanced doors of an elevator 'liatchway having an el'evatorca'r'therein comprising two vertically movable power transmitting members mounted in the hatchway, a rotatable member, connecting means between the TO": tatable member and) the power transmitting' members to move said members simultaneously in opposite directions, saidconnecting means andthe rotatable member having two dead center positions; and means effective when the eleva tor'car is stopped adjacent to a set of doors to connect the upper door of the set to one of said power transmitting members and the lower door to the other of said power transmitting-memberspthe dead'center positions of :the rotatable member correspondingto: the extreme positions of the doors, whereby the doors are moved through a predetermined distance'with' a linear veIocity'J-whioh smoothlyand gradually approaches zero at eachlimit of travel; I

14. Anoperating' mechanism for'the doors of an elevator 'hatchway having an elevator car therein comprising a power transmitting means extending vertically of the hatchway, a rotatable means effective whenthe elevator car is stopped :adjacent' to a door to cause engagement of the corresponding clutch, the dead center positions 'of the rotatable'member corresponding to the extreme positions of the doors, whereby the I JAMES E. BANCROFT- "doors are moved through a predetermined dis- 'tance with a linear velocity which smoothly and gradualy approaches zero at each limit of travel. 

